I'm just going to mount the engine normally, no silly spacers. I'll see about making my own clamp, I don't know if I'll have time in Machine Tool I to do any personal projects. Even if I don't have access to a laythe and a bridgeport, I said it in another thread but it could be done easily enough with hand tools and a power drill out of mild steel bar stock.
Will post pictures tomorrow, but I've decided to reorient the project. I'm going back to the single speed drive train for the engine but I want to make a drive by wire system and have it be pedal assist. But before that I want to try drop bars and a friction shifter as the throttle. My hope is that it'll make the ride less "hands on" when it comes to managing the engine so I can have a riding experience where the engine is helping the rider rather than the other way around.
I know I could get a more powerful engine, but I've grown fond of this kit and I don't want to give up on making it fun for me to ride.
While the PAS is completely possible, and would be very cool, if a simple friction shifter works well enough, then I'll save my time and money. Plenty of people have done diy drive by wire in rc and motorsports projects, and it would be very easy to program, especially with my occupational training, but it would be relatively expensive. My estimation is at least $200 to build a sturdy enclosure and purchase the electronics.
I've got a coaster brake to upgrade, and some components to "modernize" the bike that need to be installed. I've got a seat post that will let me use a saddle I really like, and an ashtabula to BSA bottom bracket adapter.